A top Justice Department official involved with the probe of Hillary Clinton's emails gave her campaign chair, John Podesta, a "heads up" about upcoming testimony and court filings related to the email controversy.

In an email sent in May of last year to Podesta, Peter Kadzik, assistant attorney general, wrote about his agency's impending appearance before the House Judiciary Committee and warned that the Justice Department representative in question could face inquiries about the emails.

Kadzik also warned that the State Department had filed new documents in an open records case that ultimately led to the release of all 55,000 of her emails. He warned Podesta that the production process could stretch into 2016.

Podesta forwarded the warning on to other high-level campaign aides and told them Kadzik had flagged upcoming "mischief" related to the email controversy.